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1954-55 Theatre Catalog, 12th Edition, Page 152 (118)

1954-55 Theatre Catalog, 12th Edition
1954-55 Theatre Catalog
1954-55 Theatre Catalog, 12th Edition, Page 152
Page 152

1954-55 Theatre Catalog, 12th Edition, Page 152

CWide Screens For Drive-Ins

An Analysis of the Various Factors to he Considered In Construction of Wide Screen Towers for Drive-Ins

BRIEF: When it became apparent that the wide screen . . . and particularly CinemaScope . . . would come into widespread use .' . . it quickly became clear that the thousands of drive-in theatres could not be excluded . . . However . . . the problems of installing a wide screen system in an outdoor theatre are much greater than in the conventional motion picture theatre . . . One of the major areas of difficulty is the screen tower . . . In most cases it is necessary to more than double the screen size . . . and this involves many knotty problems.

This article . . . which has been prepared by one of the leading experts in the construction of drive-in screens . . . underlines the most important factors to be considered when erecting a new

wide screen tower . . . The author covers such points as curvature . . . tilt . . . optics . . . wind load . . . and safety

factors . . . The driveein operator who is thinking of installing a wide screen owes it to himself to take advantage of the information to be found herein.

When CinemaScope, and the other wide screen systems made their bow the average drive-in operator probably felt that he would just have to be a







By JOHN 812an

President, Selby Industries, Inc.

spectator, since it appeared that the equipment necessary for the showing of a process like CinemaScope could never practically be adapted for the outdoors. However, as the wide screen came into popular favor, and as the early CinemaScope productions began to break house records all over the country in conventional theatres, it was obvious that the outdoor theatre could not be excluded for a very long period of time. One of the major barriers was hurdled when the restriction of CinemaScope to only those theatres equipped with stereos phonic sound, was lifted.

Manufacturers began to improve and adapt their equipment to meet the demands of wide screen projection in the drive-in. The greatest problem appeared to center around the screen tower. The primary question was, ncan we erect screens of the size and shape necessary to project in the proper aspect ratio and still make them safe from an engineering point of viewiw The ever increasing number of drive-ins that are playing CinemaScope product today testines that this problem is being licked.


Factors to Be Considered

It is important to remember that the finew look" of drive-in theatre screen towers is not only an increase in the aspect ratio size for CinemaScope, but also increased size curvature and tilt.

A typical 700 to 900 car drive-in, equipped for the anamorphic process, is now using a picture size of perhaps 45 by 100 feet-this is more than twice the former size, in most cases. The additional light that is required for this larger area may be obtained partly from larger lamphouses, faster lenses, and longer projection throws. A projection throw of 350 to 400 feet appears to be best for the average picture since it permits the use of the most efficient four inch focal length lenses for wide screen, and six inch base lenses for CinemaScope. To attempt a larger picture with the old 225 foot throw would make it necessary for the projectionist to use focal lengths much too short for maximum light transmission and good resolution. Since light and resolution are perhaps the two most difficult things to obtain in wide screen projection, it is easy to understand why the use of the proper focal length lenses is of such importance.

Tilt and Curvature

Although the taking of the steps just discussed are valuable contributing factors. the major increase in picture brightness is achieved by concentrating refiected light projected to the screen, and back to the customers, by proper tilt and curvature of the screen tower. Tilting the screen to an angle equal to the projection angle, and curving to a radius equal to the projection throw reflects light to the area of maximum car density, rather than to the sky or to the side areas. Curving is also important to achieve uniformity of brightness on the far side areas.

The value of directed redection is greater with gloss surfaces. Flat diffusing surfaces, such as dead flat white paint (when dry) require the least precision, but conversely, are the lowest in efficiency.

Optical Functions

In designing and building a drive-in screen tower structure, a full understanding of its optical fuhction is necessary, for the curvature and tilt of the steelwork forms the giant reflector surface.

The exhibitor who is installing a wide screen tower in a new theatre must understand the need for a long enough

THIS DIAGRAM illustrate: how a drivo-in acroon tow" should be constructed ID that it will ho strong anoth Io with-land a ham wind atom.


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1954-55 Theatre Catalog, 12th Edition, Page 152